Speaker Back Cavity

ABSTRACT

An apparatus including a sound transducer; and a housing having the sound transducer connected thereto. The housing forms a substantially sealed air space back cavity acoustically coupled to the sound transducer. The housing includes a housing member having a first dividing structure located in the back cavity to connect two adjacent air mass sections of the back cavity, where the dividing structure includes at least one aperture to permit travel of sound waves through the at lease one aperture between the air mass sections.

BACKGROUND

1. Technical Field

The exemplary and non-limiting embodiments relate generally to a soundtransducer and, more particularly, to a back cavity for a soundtransducer.

2. Brief Description of Prior Developments

A speaker in a portable electronic device, such as a mobile phone forexample, often has a back cavity for acoustic purposes.

SUMMARY

The following summary is merely intended to be exemplary. The summary isnot intended to limit the scope of the claims.

In accordance with one aspect, an example embodiment is provided in anapparatus including a sound transducer; and a housing having the soundtransducer connected thereto. The housing forms a substantially sealedair space back cavity acoustically coupled to the sound transducer. Thehousing includes a housing member having a first dividing structurelocated in the back cavity to connect two adjacent air mass sections ofthe back cavity, where the dividing structure includes at least oneaperture to permit travel of sound waves-through the at least oneaperture between the air mass sections.

In accordance with another aspect, an example method comprises providinga sound transducer; connecting a housing member to the sound transducer,where the housing member comprises a wall establishing a perimeter of aback cavity area for the sound transducer, where the wall forms the backcavity area on a single first side of the housing member, where thehousing member comprises a first dividing structure located in the backcavity area connecting two adjacent air mass sections of the back cavityarea; and connecting the first side of the housing member to at leastone second member to substantially close the back cavity area, where thewall and the first dividing structure attach to the at least one secondmember to form a substantially sealed air space back cavity acousticallycoupled to the sound transducer.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other features are explained in the followingdescription, taken in connection with the accompanying drawings,wherein;

FIG. 1 is a front view of an example embodiment of an apparatuscomprising features as described herein;

FIG. 2 is a rear view of the apparatus shown in FIG. 1;

FIG. 3 is an exploded perspective view of components of the speaker andits housing member shown in FIG. 2;

FIG. 4 is a perspective view of an alternate embodiment of one of thecomponents shown in FIG. 3;

FIG. 5 is a perspective view of other possible components of theapparatus shown in FIGS. 1-3;

FIG. 6 is a bottom plan view of the housing member shown in FIG. 3;

FIG. 6A is a schematic cross section view of the speaker and housingmember shown in FIGS. 3 and 6 attached to a printed circuit board of theapparatus shown in FIGS. 1-2;

FIG. 7 is a bottom plan view of the housing member shown in FIG. 6, butwithout the dividing structures;

FIG. 8 is a graph of speaker frequency response at 1 Volt for use withthe housing member shown in FIG. 6 versus the housing member shown inFIG. 7;

FIG. 9 is a graph of simulated speaker frequency response at 700 mV foruse with the housing member shown in FIG. 6 versus a housing membersimilar to that shown in FIG. 6 but having only one dividing structurerather than two dividing structures;

FIG. 10 is an enlarged view of a portion of the graph shown in FIG. 9;

FIG. 11 is a view as in FIG. 10 of simulated speaker frequency responseat 700 mV with use of the housing member shown in FIG. 7 versus ahousing member at in FIG. 6 but having only one dividing structure;

FIG. 12 is a graph illustrating design limits for a speaker and samplespeaker frequency responses for a speaker using the housing member shownin FIG. 7; and

FIG. 13 is a graph similar to FIG. 12 illustrating the design limits andsample speaker frequency responses for a speaker using the housingmember shown in FIG. 6.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to FIG. 1, there is shown a front view of an apparatus 10incorporating features of an example embodiment. Although the featureswill be described with reference to the example embodiments shown in thedrawings, it should be understood that features can be embodied in manyalternate forms of embodiments. In addition, any suitable size, shape ortype of elements or materials could be used.

The apparatus 10 may be a hand-held portable apparatus, such as acommunications device which includes a telephone application forexample. In the example shown the apparatus 10 is a smartphone whichincludes a camera and a camera application. The apparatus 10 mayadditionally or alternatively comprise an Internet browser application,a video recorder application, a music player and recorder application,an email application, a navigation application, a gaming application,and/or any other suitable electronic device application. In an alternateexample embodiment the apparatus might not be a smartphone.

Referring also to FIG. 2, the apparatus 10, in this example embodiment,comprises a housing 12, a touchscreen 14, a receiver 16, a transmitter18, a controller 20, a rechargeable battery 26 and a camera 30. However,all of these features are not necessary to implement the featuresdescribed below. The controller 20 may include at least one processor22, at least one memory 24, and software 28. The electronic circuitryinside the housing 12 may comprise at least one printed wiring board(PWB) 21 having components such as the controller 20 thereon. Thereceiver 16 and transmitter 18 form a primary communications system toallow the apparatus 10 to communicate with a wireless telephone system,such as a mobile telephone base station for example.

In this example, the apparatus 10 includes the camera 30 which islocated at the rear side 13 of the apparatus, a front camera 32, an LED34, and a flash system 36. The LED 34 and the flash system 36 are alsovisible at the rear side of the apparatus, and are provided for thecamera 30. The cameras 30, 32, the LED 34 and the flash system 36 areconnected to the controller 20 such that the controller 20 may controltheir operation. In an alternate example embodiment she rear side maycomprise more than one camera, and/or the front side could comprise morethan one camera. The apparatus 10 includes a sound transducer providedas a microphone 38. In an alternate example the apparatus may comprisemore than one microphone. The apparatus 10 includes a sound transducerprovided as an earpiece 40, and a sound transducer provided as a speaker42. More or less than one speaker may be provided.

Features as described herein relate to audio reproduction, such as in amobile communication device for example. More specifically, features mayrelate to an enclosure for an integrated hands-free (IMF) loudspeaker,such as the speaker 42 for example. Such a loudspeaker most commonly hasone side enclosed in a sealed air space, hereafter known as the backcavity, while the other side of the loudspeaker is coupled to a soundoutlet in the outer cover of the mobile communication device. In theembodiment shown in FIG. 2, the back cover 13 comprises sound holes 44for the speaker 42. However, in alternate embodiments the sound holesand speaker could be located at any suitable location on the apparatus.

Mobile devices usually have severely constrained spaces inside them. Inspite of this, a back cavity must be arranged for the IMF loudspeaker.This means that the back cavity often has to have an elongated shape.For good audio performance, the opposite (i.e. a compact shape withoutelongated parts) is better. Elongated shapes of such cavities usuallycause artifacts such as higher modes that result in peaks and dips inthe frequency response of the IMF. Pronounced peaks and dips areproblematic not only because they reduce sound quality, but also becausethey may keep the IHF from passing audio reproduction requirements, andfurthermore because they may lead to physical failure of the speaker.Physical failure can happen such as if a mode happens to coincide with avibration mode in the lead wires of the loudspeaker for example. Even ifthe frequency response of an IHF does fit inside given specificationlimits, nigh peaks and dips are undesirable as they leave less marginfor inevitable variation in performance due to tolerances.

Referring also to FIG. 3, in this example the speaker 42 is provided inthe form with a speaker box. In particular, for this example the speaker42 comprises a housing component 46, a yoke 48, a magnet 50, a plate 52,metal inserts 54, a electromagnetic coil 56, a membrane 58, a done 60and a liner or protective film 62. This is merely an example of some ofthe components. In alternate embodiments other types of components maybe used. For example, FIG. 4 shows a front gasket 64 rather than use ofthe protective film 62. FIG. 5 also shows a microphone seal 66 and aprinted circuit board (PCB) gasket 68 which could be used with thehousing component 46. The housing component 46, such as made of moldedplastic for example, is configured to have the other components attachedthereto, such as including the printed circuit board 21 for example, toclose the back cavity of the speaker box.

In this example the housing component 46 helps to form a speaker boxwhich is located inside the housing 12. In an alternate example a sameor similar cavity structure provided by the speaker box may be designedinside an electronic device where the electronic device also comprises aspeaker transducer so that such cavity structure can be acousticallycoupled to the sneaker transducer. In this regard the apparatus could bea standalone speaker box, so that it could be placed inside theelectronic device, or alternatively the apparatus may have such a cavityarrangement created inside the electronic device without accommodatingany removable/attachable speaker box. Basically the housing could be aspeaker box, but such air space could be formed by different sections ofthe electronic device. Therefore, the housing 12 of the electronicapparatus 10 could form such cavity; entirely or at least partially.

Referring also to FIG. 6, the opposite side of the housing component 46is shown. The housing component 46 has a receiving area 70 which isconfigured to receive the components 48-60. The housing component 46 isa one-piece member having integrally formed cavities 72, 74 which, alongwith an area directly under the transducer, form the back cavity for thespeaker. In this example the two cavities 72, 74 are separated by thearea directly under the sound transducer. The upstanding ribs or wails76 surrounding the cavities 72, 74 are attached to another component,such as the PCB 21 as shown in FIG. 6A for example, to close thecavities 72, 74. Thus, the PCB may function as a housing member to formthe back cavity with the housing component 46. In an alternate example,another member(s) could be used with the housing member 46 to close theback cavity, or the housing member could provide the closed back cavityitself as a one piece member. The components 48-62 close off sheaperture into the receiving area 70. Thus, the cavities 72, 74 form asealed air space to function as the back cavity for the speaker.

Features as described herein comprise providing one or more dividingstructures (walls) 78, 79 having one or more apertures 80, 81 in thecavities 72, 74. For illustration purposes only, FIG. 7 shows thehousing member 46 without the dividing structures 78, 79. As can beseen, the cavities 72, 74 for the back cavity have a relatively simplegenerally block shape. For audio performance, the back cavity formed bythe relatively simple, block shaped cavities 72, 74 provides aconcentrated area, but would still be elongated enough to cause highermodes. Thus, the dividing structures are added to thereby provide acompact shape without elongated parts to provide better audioperformance than a back cavity having an elongated shape.

In this example embodiment, the first dividing structure 78 is astraight wall with a plurality of the apertures 80 therethrough. Thefirst dividing structure 78 in the first cavity 72, because of theapertures 80, has a general grid or lattice shape. The ends or surfaces82 of the dividing structure 78 are at the same plane as the ends of thewalls 76. Thus, the surfaces 82 may be sealed onto the PCB with thewalls 76. This is illustrated by FIG. 6A. In an alternate example, alittle gap may be provided between 82 and the PCB in order to cause asmall leak; which usually has the effect of providing some acousticdamping. Pressure waves must travel through the apertures 80 in order totravel between the two cavity sections 72 a, 72 b of the cavity 72. Thecavity sections 72 a, 72 b form two adjacent air mass holding sectionsof the back cavity. The size, location and shape of the apertures 80 maybe selected so as to provide a tuning function, so as to attenuateand/or shift the modes to have a less detrimental effect on thefrequency response, sound quality and loudspeaker lifetime.

In this example embodiment, the second dividing structure 79 has twostraight wails 84 forming a conduit therebetween by the aperture 81. Theconduit may be considered a tuned pipe, or port or channel. The ends orsurfaces 86 of the dividing structure 79 are at the same plane as theends of the walls 76. Thus, the surfaces 86 may be sealed onto the PCBwith the walls 76. In the alternate example where a small gap isprovided between the ends 86 and the PCB, the cavity sections 74 a, 74 bare still at the same plane as the ends of the walls 76. Pressure wavesmust travel through the aperture 81 in order to travel between the twocavity sections 74 a, 74 b of the cavity 74. The two cavity sections 74a, 74 b form two adjacent air mass holding sections of the back cavity.The size, location and shape of the aperture 81 may be selected so as toprovide a tuning function, so as to attenuate and/or shift the modes tohave a less detrimental effect on the frequency response, sound qualityand loudspeaker lifetime.

In one example embodiment, the length of each half 72, 74 of the backcavity is about 24 mm, and has a width of about 9 mm. Thus, the ratio oflength to width is about 2.67:1 or about 37.5%. In other examples, inorder to provide the non-elongate, generally block shaped back cavitywithout elongated parts, the ratio may be about 4:1, or 3:1, or less.The height in this example is about 2.5 mm. The dimensions may varyalong the length of the cavity. The first divider 78 has three slots 80,each may have the same height as the cavity (perhaps with a slight gapfor dampening as mentioned above), with a width of about 0.6 mm, and alength (in air flow direction) of about 0.9 mm. The second divider 79is, in effect, a rectangular tube having again the same height as thecavity, a width of about 0.8 mm, and a physical length of about 4.5 mm(the effective acoustical length is perhaps 8 mm, because of the wallsclose to the ends of the tube). In this example embodiment the totalacoustic volumes for the respective cavities are:

-   -   Cavity 72 having 3 slots=about 0.55 cm³,    -   Cavity 74 having tube=about 0.43 cm³.        The size of the section 72 a relative to the size of the section        72 b is about 50 percent or smaller, but it may be greater. The        size of the section 74 a relative to the size of the section 74        b is about 50 percent or smaller, but it may be greater. Please        note that the specific specification numbers and dimensions        given above these are merely for an example, and should not be        considered as limiting. The slots and wall locations could also        be different as long as they still work for the given case. The        sections 72 a, 72 b and 74 a, 74 b are all located in a same        plane, side-by-side, and not stacked one on top of the other. In        an alternate example the tube may also be shorter than the        cavity in order to provide a small gap for damping.

There is no principal difference between how a series of slots, or asingle tube, work. Both produce an additional acoustic mass at the givenlocation, and it may be tuned according to the cavity shape and volume.One muse also consider what dimensions are achievable by moldingplastic. The angles 88, 89 of the dividing structures may be varied (orother shapes provided) to tune the reflections and pressure flows. Theangle typically has only a negligible or non-existent effect onreflections; when dimensions are as small as here. However, thestructures may be angled such as to merely avoid injection gates in themold chamber, and components on the PWB for example. A tuned pipe effectis provided by the addition of the dividing structures, as a tunedexpansion chamber, while still keeping the general block shape of theback chamber shown in FIG. 6.

There are many possible ways to tune the dividing structures. In oneexample, a wall and aperture may be provided just to slightly shift amode (from the loudspeaker's point of view) to a less risky frequency,to avoid failures of, for example, lead wires. In another example, awall and aperture may be tuned to act as an acoustic low-pass filterthat decouples an outer part of the cavity from an inner part of thecavity adjacent to the loudspeaker 42, above a given frequency, as ameans of avoiding one or more higher modes. In yet another example, theend result may just be several weaker modes instead of one or a coupleof strong modes, to help to flatten the frequency response and/or fit itinside given specification limits.

If the back cavity consists of two or more separate parts (branches),such as 72 and 74 for example, each of them may have its own dividingstructure(s), or there may be two or more dividing structures in series;one after the other for example.

The angles 88, 89 of the dividing structures and location of dividingstructures might not be determined purely by acoustics, but may alsohave to be adjusted such as according to locations of other interveningcomponents inside the back cavity and/or injection gates in the mold forexample. In the example embodiment shown in FIG. 6, the right sidedividing structure 79 effectively consists of a tube (in order toproduce a higher acoustic mass) whereas the left side dividing structure78 instead has three slits (producing a lower acoustic mass and somewhathigher acoustic resistance in this case, with these dimensions).

Referring also to FIG. 8, the graph shows an example of a measuredeffect of having the above-mentioned dividing structures in the backcavity. Speaker frequency response at 1 V is shown. Line 90 shows theresponse for the back cavity shown in FIG. 7 which does not have thedividing structures. Line 92 shows the improved performance with thedividing structures 78, 79 in place in accordance with the example shownin FIG. 6. The smaller difference between minimum and maximum soundpressure levels for the line 92 versus line 90, especially in the 4-6kHz range, should be noted.

To this implementation, further damping elements may or may nor beadded. For example, one or more dividing structures may be deliberatelymade slightly shorter than the surrounding wails in order to produce asmall leakage acting as an additional acoustic resistance, or additionaldamping foam may be added to one or more dividing structures.

An embodiment may have merely one dividing structure, two dividingstructures, or more than two dividing structures. Referring also to FIG.9, frequency responses obtained from simulations for the back cavity ofFIG. 6 (having two dividing structures) versus a back cavity having onlyone dividing structure is shown. Line 94 represents when one divider isused, and line 96 represents when two dividers are used. FIG. 10 showsan enlarged view of the lines 94, 96 between 1000-8000 Hz. Referringalso to FIG. 11, frequency responses obtained from simulations for theback cavity having only one dividing structure is shown by line 94, andline 98 represents when no dividers are used as in the back cavity ofFIG. 7. These figures help to clarify the effect of one divider versususe of two dividers and versus when no dividers are used.

Referring also to FIG. 12, a speaker will ordinarily be designed to fitwithin certain upper and lower speaker limits 100, 102 of frequencyresponse. FIG. 12 shows samples of speaker frequency response at 700 mWfor using the back cavity shown in FIG. 7 which does not have anydividing structures in the back cavity. As can be seen, some of thefrequencies of the samples 104 exceed the limits for the speaker. Byexceeding the limits, this results in reduced frequency response, soundquality and perhaps loudspeaker lifetime.

Referring also to FIG. 13, the same limits are shown for the samespeaker, but with use of the back cavity having the dividing structuresof FIG. 6. As can be seen, the frequency response of the new samples104′ has been changed to no longer exceed the limits 100, 102. Frequencyresponse has been flattened and shifted from the response with nodividing structures (FIG. 12) versus the response with two dividingstructures (FIG. 13). Compare also line 98 (no dividing structures) toline 94 (one dividing structure) to line 96 (two dividing structures).

Features as described herein allow for a compact back cavity having arelatively simple, generally block shape without elongated parts. Theoverall shape (without the dividing structures) is still too elongated,but rather than having one strong mode, with the addition of thedividing structures provides several weaker modes. Inside the generallyblock shaped back cavity are one or more dividing structures withaperture(s) which have been tuned to change the frequency response ofthe speaker.

For audio performance, the back cavity formed by the relatively simple,block shaped cavities 72, 74 provides a compact shape without elongatedparts to provide better audio performance than a back cavity having anelongated shape. Without an elongate shaped back cavity, artifacts suchas higher modes that result in peaks and dips in the frequency responseof the IHF are avoided. Without an elongate shaped back cavity,problematic pronounced peaks and dips, which otherwise would reducesound quality, are avoided, perceived sound quality is improved, and alikelihood of premature failure is reduced. A dividing structuredecouples an outer part of the back cavity from an inner one at higherfrequencies and, thus, effectively reduces the cavity size at higherfrequencies, meaning that the cavity at higher frequencies effectivelybecomes more compact.

With features as described herein, the back cavity need not be coupledto ambient air through an acoustic opening(s). Also, the other side ofthe loudspeaker need not be coupled to the ambient air through acousticopening(s). In an example embodiment, the back cavity (which is dividedby the added constrictions 78, 79) is not coupled to ambient air (exceptperhaps for a small pressure-equalizing leak that has no appreciabledirect effect on the acoustic performance), and only one side of theloudspeaker is coupled to the ambient air.

In an example embodiment, there may be provided a substantially sealedback cavity, acoustically coupled to a speaker component, whereinpre-determined dividing walls (or a tube structure) are able to smooththe frequency response by trying to eliminate the effect of unwantednotches. It could be considered that these dividing structures may beconstructed for optimizing a tuned frequency response rather than atuning of the frequency response based on the cavity, aperturecombinations.

An example apparatus 10 may comprise a sound transducer 42; and ahousing 12 having the sound transducer connected thereto (or otherwisepositioned, integrated, placed, located, provided with the housing),where the housing forms a substantially sealed air space back cavitywith the sound transducer, where the housing comprises a one-piecehousing member 46 including a first dividing structure 78 or 79 locatedin the back cavity to separate two adjacent air mass holding sections ofthe back cavity, where the dividing structure comprises at least oneaperture to limit travel of pressure waves through the at least oneaperture between the sections.

The housing member may be a one-piece housing member with the firstdividing structure integrally formed with the one-piece housing memberat a first side of the one-piece housing member, where the two adjacentair mass holding sections are located at the first side of the one-piecehousing member. The one-piece housing member may comprise a seconddividing structure located in the back cavity to separate two otheradjacent air mass holding sections of the back cavity. The firstdividing structure may comprise a wall having a plurality of aperturestherethrough. The first dividing structure may comprise two spacedelongate walls with an aperture therebetween forming an elongate tunedpipe area. The first dividing structure may comprise an angled elongatewall. A size of the two adjacent air mass holding sections relative toeach other may be about 50 percent or greater. Two air mass holdingsections of the back cavity may be located in a same plane along a firstside 76 of the one-piece housing member. The apparatus may furthercomprise a printed circuit board 21 connected to a first side of theone-piece housing member to substantially seal the back cavity. Theapparatus may further comprise a printed circuit board connected to thesound transducer; at least one processor connected to the printedcircuit board; at least one memory connected to the printed circuitboard; at least one electronic display connected to the printed circuitboard; and at least one battery connected to the printed circuit board.The apparatus may further comprise means for smoothing frequencyresponse of the sound transducer, where the means for smoothingfrequency response comprises the first dividing structure.

An example method may comprise providing a sound transducer; connectinga housing member to the sound transducer, where the housing membercomprises a wall establishing a perimeter of a back cavity area for thesound transducer, where the wall forms the back cavity area on a singlefirst side of the housing member, where the housing member comprises afirst dividing structure located in the back cavity area separating twoadjacent air mass holding sections of the back cavity area; andconnecting the first side of the housing member to at least one secondmember to substantially close the back cavity area, where the wall andthe first dividing structure attach to the at least one second member toform a substantially sealed air space back cavity with the soundtransducer.

The first dividing structure may be integrally formed with the housingmember, and where the two adjacent air mass holding sections are locatedat a same exterior first side of the one-piece housing member. Thehousing member may comprise a second dividing structure located in theback cavity to separate two other adjacent air mass holding sections ofthe back cavity, where free ends of the first and second dividingstructures are attached to one at lease one second member. The firstdividing structure may comprise a wall having a plurality of aperturestherethrough, where a free end of the wall is attached to the at leastone second member. The first dividing structure may comprise two spacedelongate walls with an aperture therebetween forming an elongate tunedpipe area, where free ends of the two walls are attached to the at leastone second member. The first dividing structure may comprise an angledelongate wall forming an angled joint between the two air mass holdingsections. A size of the two adjacent air mass holding sections relativeto each other, after the housing member is attached to the at least onesecond member, may be about 50 percent or greater. The two air massholding sections of the back cavity may be located in a same plane alonga first side of the housing member, where the first side is attached tothe at least one second member. The at least one second member maycomprise a printed circuit board connected to a first side of theone-piece housing member to substantially seal the back cavity area.

It should be understood that the foregoing description is onlyillustrative. Various alternatives and modifications can be devised bythose skilled in the art. For example, features recited in the variousdependent claims could be combined with each other in any suitablecombination(s). In addition, features from different embodimentsdescribed above could be selectively combined into a new embodiment.Accordingly, the description is intended to embrace all suchalternatives, modifications and variances which fall within the scope ofthe appended claims.

What is claimed is;
 1. An apparatus comprising: a sound transducer; anda housing having the sound transducer connected thereto, where thehousing forms a substantially sealed air space back cavity acousticallycoupled to the sound transducer, where the housing comprises a housingmember including a first dividing structure located in the back cavityto connect two adjacent air mass sections of the back cavity, where thedividing structure comprises at least one aperture to permit travel ofsound waves through the at least one aperture between the air masssections.
 2. An apparatus as in claim 1 where the housing member is aone-piece housing member having the first dividing structure integrallyformed with the one-piece housing member at a first side of theone-piece housing member, where the two adjacent air mass holdingsections are located at the first side of the one-piece housing member.3. An apparatus as in claim 2 where the one-piece housing membercomprises a second dividing structure located in the back cavity toconnect two other adjacent air mass holding sections of the back cavity.4. An apparatus as in claim 1 where the first dividing structurecomprises a wall having a plurality of apertures therethrough.
 5. Anapparatus as in claim 1 where the first dividing structure comprises twospaced elongate walls with an aperture therebetween forming an elongatetuned conduit area.
 6. An apparatus as in claim 1 where the firstdividing structure comprises an angled elongate wall.
 7. An apparatus asin claim 1 where a size of the two adjacent air mass holding sectionsrelative to each other is about 50 percent or less.
 8. An apparatus asin claim 1 where two air mass holding sections of the back cavity arelocated in a same plane along a first side of the housing member.
 9. Anapparatus as in claim 1 further comprising a printed circuit boardconnected to a first side of the housing member to substantially sealthe back cavity.
 10. An apparatus as in claim 1 further comprising: aprinted circuit board connected to the sound transducer; at least oneprocessor connected to the printed circuit board; at least one memoryconnected to the printed circuit board; at least one electronic displayconnected to the printed circuit board; and at least one batteryconnected to the printed circuit board.
 11. An apparatus as in claim 1further comprising means for smoothing frequency response of the soundtransducer, where the means for smoothing frequency response comprisesthe first dividing structure.
 12. A method comprising: providing a soundtransducer; connecting a housing member to the sound transducer, wherethe housing member comprises a wall establishing a perimeter of a backcavity area for the sound transducer, where the wall forms the backcavity area on a single first side of the housing member, where thehousing member comprises a first dividing structure located in the backcavity area connecting two adjacent air mass sections of the back cavityarea; and connecting the first side of the housing member to at leastone second member to substantially close the back cavity area, where thewall and the first dividing structure attach to the at least one secondmember to form a substantially sealed air space back cavity acousticallycoupled to the sound transducer.
 13. A method as in claim 12 where thefirst dividing structure is integrally formed with the housing member,and where the two adjacent air mass sections are located at a sameexterior first side of the housing member.
 14. A method as in claim 12where the housing member comprises a second dividing structure locatedin the back cavity to connect two other adjacent air mass sections ofthe back cavity, where free ends of the first and second dividingstructures are attached to the at least one second member.
 15. A methodas in claim 12 where the first dividing structure comprises a wallhaving a plurality of apertures therethrough, where a free end of thewall is attached to the at least one second member.
 16. A method as inclaim 12 where the first dividing structure comprises two spacedelongate walls with an aperture therebetween forming an elongate tunedconduit area, where free ends of the two walls are attached to the atleast one second member.
 17. A method as in claim 12 where the firstdividing structure comprises an angled elongate wail forming an angledjoint between the two air mass sections.
 18. A method as in claim 12where a size of the two adjacent air mass sections relative to eachother, after the housing member is attached to the at least one secondmember, is about 50 percent or less.
 19. A method as in claim 12 wherethe two air mass sections of the back cavity are located in a same planealong a first side of the housing member, where the first side isattached to the at least one second member.
 20. A method as in claim 12where the at least one second member comprises a printed circuit boardconnected to a first side of the housing member to substantially sealthe back cavity area.